This invention arose in the design of a simulator for training crew for aircraft, ships and land vehicles and relates particularly to computer generated imagery techniques for such a simulator.
Particularly where it is desired to simulate a scene for training a ship's crew or captain, or where it is desired for more than one person to view the same screen, it is necessary to provide a particularly large screen, which preferably curves around the observer so as to provide a wide angle of view. In such circumstances it may be necessary to illuminate the screen using two or more projectors at different positions. Initial attempts to build a suitable multiple-projector display like this suffered from the problem that a dividing line could be seen where the part of the image displayed by one projector joined another part displayed by another projector. This dividing line arose because the observer, when located at certain positions in front of the screen was more directly in line with one projector than the other. Thus, to reach the observer, light from one projector had to be diffused through a larger angle than that from the other projector. Hence one part of the picture appeared less bright than the other: thus resulting in the dividing line between the parts of the picture.